Must be vacuum secondaries, must be fairly new and unmodified, and I'd like the idle-eze adjustment.

 

get a double pumper and go faster in the 1/4 mile

 

From what I've heard, DP's and automatics don't work too well together, especially for street driving.

 

Most demons are double pumpers. Demon is pretty much just like holley, for the exception of a couple of things. Ive never had any problems with my Mighty demon and my automatic

 

The car just runs a little rich, and I think it's not getting enough air. Right now, it's got a Holley 750 VS on it, so I figured going with a bigger one would do the trick. I like the demon carbs because the new ones have the idle-eze valve so you can bleed more air into the idle circuitry without tearing everything apart and modifying it. Maybe a 750 would be enough for me; I don't know. How do you drive your car with the double pumper. Somebody told me if you run a DP carb on an auto car, you have to let off of the gas slightly when you shift or you will just bog down the engine, and that also when taking off from a dead stop, you can't just mash the gas or you will flood it. Are these just myths, or is there some truth. I just sold a Holley 800 DP to a guy on this board that I haven't had time to rebuild. I didn't give any thought to using it, because I didn't think I could run a DP. Maybe I should start a thread in the carb section.

 

Well how many Hp do you have? I have 500 HP and 505 lbs of torque, so my 383 loves every bit of the carb.

 

Haven't had time to dyno it yet, but a guy in town said his desktop dyno gives HP readings close to 500 with low to mid 12 sec 1/4 mile, but I think me not having true dual exhaust is keeping it from achieving that (Don't ever get Alsoton SFC's and Spohn crossmember if you want true duals). I tried the G-tech on it one day when it was cold outside, and it read like 280. I think with a good tune on a dyno pull, it should have an honest 300+ rwhp.

 

double pumper and big stalls are fine together. I have a 750 dp and a 3600 stall and no bog whatsoever. IF your 750 VS is running rich at idle then you need to reset the mixture screws. If your cam is larger then you need more initial timing and that is your problem. For my cam I just lock the timing out and it cleaned up the super rich idle instantly.

 

I've screwed the mixture screws in all the way, backed them out 1.25 turns and tried to adjust from there, and it just doesn't work. I've also replaced the power valve due to backfires I've had. Something I've forgot to mention is that sometimes when I try to start it, it loads up and will actually backfire through the carb. If this is a timing problem as you suggest, how do I lock out the timing? I've got a Mallory 85 series HEI with vacuum advance. Do I need to remove the vacuum advance? If so, what do I put in its place?

Thanks,
Eric

 

search for limiting mechanical advance on the boards, there's tons of threads.

 

No longer need one. It seems I have a timing issue. Thanks to everyone who provided me with help.